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Dietary pectic oligosaccharide administration improves the growth performance and immunity in weaned pigs infected by rotavirus Hao Chen, Haiyan Hu, Daiwen Chen, Jun Tang, BING YU, Junqiu Luo, Jun He, Yuheng Luo, Jie Yu, and Xiangbing Mao J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.7b00039 • Publication Date (Web): 21 Mar 2017 Downloaded from http://pubs.acs.org on March 25, 2017
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Journal of Agricultural and Food Chemistry
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Dietary pectic oligosaccharide administration improves the growth performance
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and immunity in weaned pigs infected by rotavirus
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Hao Chen†, §, Haiyan Hu†, §, Daiwen Chen†, §, Jun Tang†, §, Bing Yu†, §, Junqiu Luo†, §,
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Jun He†, §, Yuheng Luo†, §, Jie Yu†, §, Xiangbing Mao†, §, *
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†
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Republic of China
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§
Animal Nutrition Institute, Sichuan Agricultural University, Ya’an, Sichuan, People’s
Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education,
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China, Ya’an, Sichuan, People’s Republic of China
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*
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+86-835-2885106, E-mail:
[email protected].
Corresponding
author,
Associate Professor
Xiangbing
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Mao,
Phone/Fax:
Journal of Agricultural and Food Chemistry
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ABSTRACT
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Rotavirus infection is one of the main pathogenic causes of gastroenteritis and
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diarrhea in children and young animals. The present study aimed to determine
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whether dietary pectic oligosaccharide (POS) supplementation could improve the
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growth performance and immunity in weaned pigs infected by porcine rotavirus
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(PRV). Twenty-eight crossbred weaned galts were randomly divided into two groups
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fed with basal diet with or without POS for 18 d. On 15th day, the PRV were orally
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infused to half of the pigs. ADFI, ADG and F/G ratio were impaired by PRV infection
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in weaned pigs (P < 0.05). PRV challenge also induced diarrhea, and enhanced serum
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levels of urea nitrogen (P < 0.05), MDA (P < 0.05), IgA (P < 0.05) and IgG (P = 0.08),
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rotavirus antibody levels in serum, jejunal and ileal mucosa (P < 0.05), IL-2 levels in
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the jejunal (P = 0.07) and ileal (P = 0.08) mucosa, but decreased digestive enzyme
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activities of the jejunal digesta (P < 0.05), concentrations of sIgA, IL-4 and IFN-γ in
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the jejunal and ileal mucosa (P < 0.05), and serum T-AOC (P < 0.05) in the weaned
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pigs. POS administration could improve the growth performance of the weaned pigs
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(P < 0.05), and enhance the serum IgA level (P < 0.05), the lipase and tryptase
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activities of jejunal digesta (P < 0.05), and the sIgA, IL-4 and IFN-γ levels of jejunal
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and/or ileal mucosa (P < 0.05) in the weaned pigs. Furthermore, supplementing POS
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in diets could alleviate diarrhea and decreasing growth performance in the weaned
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pigs orally infused by PRV (P < 0.05), increase serum, jejunal and ileal rotavirus
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antibody levels (P < 0.05), and attenuate the effect of PRV challenge on serum T-AOC
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and concentrations of IgG and MDA (P < 0.05), lipase and tryptase activities in
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Journal of Agricultural and Food Chemistry
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jejunal digesta (P < 0.05), and sIgA, IL-4 and IFN-γ levels in jejunal and/or ileal
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mucosa (P < 0.05) in the weaned pigs. These results suggest that dietary POS
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supplementation could improve the growth performance, which was possibly due that
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POS administration improved the immune function and the utilization of nutrients in
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the PRV-infection piglets. This offers a potential dietary intervention strategy against
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intestinal exposure to rotavirus in piglets.
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KEY WORDS: pectic oligosaccharide, rotavirus, immunity, growth performance,
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weaned pig.
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INTRODUCTION
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Because of the lower immune function and uncompleted-development digestive
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tract, young animals and children are prone to intestinal diseases, such as diarrhea,
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that will be harmful of growth performance
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main pathogenic causes of gastroenteritis and diarrhea in children and young animals
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4, 5
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intestine health, and induce the inflammatory response in the children and weaned
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pigs 6-8.
1-3
. Rotavirus (RV) infection is a kind of
. Moreover, some researchers also reported that rotavirus infection could impair the
Many studies have shown that some additives, including the functional
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8-12
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oligosaccharide, can decrease the diarrhea that was induced by RV in pigs
.
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Furthermore, the functional oligosaccharide has many biological virtues, including
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improving immunity, which is beneficial to the growth of children and young animals
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13-19
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the animals from the infection of some viruses and germs 20, 21. As a kind of functional
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oligosaccharide, pectic oligosaccharide (POS), which is derived from polysaccharides
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of plant cell wall, also have the similar physiological function in children and animals
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13, 22
. Furthermore, some oligosaccharide administration can, to some extent, protect
.
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Therefore, the aim of this study was to verify the hypothesis that supplementing
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POS in diets might improve growth performance and immune function of the
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PRV-infection piglets.
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MATERIALS AND METHODS
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Animals and diets
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The experimental protocol was approved by Animal Care Advisory Committee
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of Sichuan Agricultural University. Twenty-eight DLY (Duroc × Landrace × Yorkshire)
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weaned galts (7.54 ± 0.31 kg) were fed in the metabolic cages (1.5 m × 0.7 m × 1.0
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m). The pigs were fed with the experimental diets 4 times daily at 08.00, 12.00, 16.00
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and 20.00, and freely drank water. Following 3 d for orientation, these piglets were
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divided randomly into two groups on basis of body weight and litter origin, and were
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fed with basal diet (Control group, n = 14) or basal diet with 200 mg/kg apple pectic
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oligosaccharide product (POS group, n = 14) for 18 d.
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The basal diet was formulated to meet NRC (2012)
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nutrient recommendations
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for pigs (7-11 kg). Its composition and nutrient content were listed in Table 1. The
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POS group diet was formed via supplementing with 200 mg/kg apple pectic
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oligosaccharide product in basal diet. The apple pectic oligosaccharide product was
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obtained from Hebei Kena Biological Technology Co. Ltd. (Hebei, China). The
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contents of POS and corn starch are 30% and 70% in the product, respectively.
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POS were produced by pectinase hydrolysis of pectic acid with 26.6% of
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methylation, which was obtained by chemical hydrolysis of apple pectin. The high
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performance liquid chromatography (HPLC) detection showed that POS content was
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more than 55%, and monosaccharide content was more than 20% in the apple pectic
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oligosaccharide product. Analysis of the electrospray ionization-mass spectrometry
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(ESI-MS) showed that POS product mainly contain pectic disaccharide, pectic
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trisaccharide, and a high degree of polymerization of POS.
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On 15th day, all piglets were infused 5 mL of sterile NaHCO3 solution (100
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mmol/L). Then, half of piglets in two groups were orally administrated with 4 mL
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(106 Tissue culture infective dose 50 (TCID50)/mL) of PRV, and the other piglets
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were infused with 4 mL of the sterile essential medium. After PRV infusion, the
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diarrhea status of all piglets was recorded based on Table 2. Pigs were deemed
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diarrhea when their daily fecal consistency scores is ≥ 2 24. Average daily weight gain
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(ADG), average daily feed intake (ADFI) and feed/gain ratio (F/G ratio) were
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calculated via weighing body weight and feed intake of all piglets at 08.00 of d 1, 15
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and 19.
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Experimental design and sample collection
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On 19th day, following weighing, the blood of pigs were gathered through the
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jugular vein, and isolated serum samples were made by centrifuging blood at 3500 g
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for 10 min. Then, all piglets were fed with their diets. At 1.5 h after refeeding, all pigs
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were euthanized via intracardially injecting Na pentobarbital (50 mg/kg of body
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weight) and exsanguinating. The jejunum and ileum were separated, and rinsed with
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ice-cold saline. The mucosa of jejunum and ileum was gathered by scraping the gut
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wall with a glass microscope slide, and frozen in liquid nitrogen. Approximately 3 g
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of the digesta from the jejunum were collected in sterile tubes, and frozen in liquid
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nitrogen. Following collection, all samples were stored at -80°C.
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PRV preparation
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In the present study, PRV was a tissue culture-adapted Ohio State University
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(OSU) strain (ATCC #VR-893). The viral propagation, collection and titre
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determination with IPEC-J2 cells were determined as described previously 25-27.
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Analysis of the serum urea nitrogen, serum and intestinal rotavirus antibody and
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immunoglobulin (Ig) concentrations
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Serum urea nitrogen (UN) concentration was analyzed with an assay kit (Nanjing
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Jiancheng Biochemistry, Nanjing, China) on the basis of the manufacturer’s
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instructions. The rotavirus antibody (RV-Ab) concentrations in serum, jejunal and
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ileal mucosa were determined with a commercially available pig enzyme-linked
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immunosorbent assay (ELISA) kit (TSZ ELISA, Framingham, MA) on the basis of
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the manufacturer’s instructions. IgA, IgG and IgM levels in serum were analyzed with
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commercially available ELISA kits (Nuoyuan Co. Ltd., Shanghai, China).
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Analysis of the digestive enzymes activities in the jejunal digesta
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Before the determination, the samples need to homogenate pretreatment. The
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0.2-1.0 g of jejunum digesta was added into the homogenate medium (saline)
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according to the quality of volume ratio 1:9 (g/mL), and executed the ultrasonic
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pulverization, and then centrifuged at 2000 g for 10 min at 4°C. In the supernatant,
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the amylase, lipase and tryptase activities were determined by using the ultraviolet
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spectrophotometer and assay kits (Nanjing Jiancheng Biochemistry, Nanjing, China)
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on the basis of the manufacturer’s instructions.
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Analysis of the sIgA and cytokine concentrations in the jejunal and ileal mucosa
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The 100 mg of the intestinal mucosa was added into the ice-cold PBS, and
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executed the pulverization at 4°C, and then centrifuged at 5000 g for 15 min at 4°C.
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In the supernatant, the sIgA, IFN-γ, IL-2 and IL-4 concentrations were determined
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with commercially available pig ELISA kits (Nuoyuan Co. Ltd., Shanghai, China) on
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the basis of the manufacturer’s instructions.
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Analysis of the serum antioxidant capacity
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Serum malondialdehyde (MDA) concentration and total antioxidant capacity (T-AOC)
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were analyzed with assay kits (Nanjing Jiancheng Biochemistry, Nanjing, China) on
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the basis of the manufacturer’s instructions.
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Statistical analysis
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The growth performance data of all piglets before PRV challenge were analyzed
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with the unpaired t test. The other data were analyzed as a 2 × 2 factorial with the
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general linear model procedures of the Statistical Analysis Package. The model
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factors included the effects of POS administration (with or without POS in diets),
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PRV infection (PRV unchallenged or challenged), and their interaction. All data were
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analyzed with SAS (Version8.1; SAS Institute, Gary, NC). All data were indicated as
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means with their standard errors. P value less than 0.05 was considered statistical
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significance while P value less than 0.10 was considered statistical tendency.
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RESULTS
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Growth performance of weaned pigs
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During the experiment, there were not any unexpected deaths. During the trial,
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supplementing POS in the diet increased ADG and reduced F/G ratio of pigs between
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1-14 days (P < 0.05) (Table 3). However, PRV infusion reduced ADFI and ADG and
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increased F/G ratio of weaned pigs (P < 0.05). But dietary POS supplementation
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relieved the effect of PRV infection on ADFI, ADG and F/G ratio of weaned pigs (P
